1. Field of the Invention
The present invention relates to a component mounting apparatus for mounting a variety of components such as electronic components onto a circuit board, and particularly to a component mounting apparatus equipped with a plurality of component feeder tables, each component table loaded with rows of parts cassettes and having a cassette carrying section arranged detachable by means of a carrier cart.
2. Description of Related Art
In such an electronic component mounting apparatus, the parts cassettes filled with a multiplicity of electronic components and carried in rows on the component feeder table are directed to and positioned at a component pickup location in sequence where desired components are picked up from the corresponding parts cassettes and mounted onto a circuit board by a mounting head.
One of such conventional component mounting apparatuses will now be explained referring to FIG. 5.
As shown in FIG. 5, at a front side of a main body 41 of the component mounting apparatus, a board positioning unit 42 for positioning a circuit board 2 on which components are mounted, a board discharging means 43 for supplying the circuit board 2, and a board removing means 44 for removing the circuit board 2 are disposed. A component feeder unit 45 is disposed behind the main body 41. Between the board positioning unit 42 and the component feeder unit 45 is a rotary mounting head 46 for picking up the components at a component pickup location on the component feeder unit 45 and mounting them onto the circuit board 2 on the board positioning unit 42.
The component feeder unit 45 includes a couple of component feeder tables 47 and 48, each having rows of parts cassettes 49 carried in parallel with each other thereon and arranged to be separately movable along guide rails 50 in lateral directions, i.e. along the direction of the rows of the parts cassettes 49. While the component feeder table 47 feeds the components, the component feeder table 48 is at its retracted position where exhausted parts cassettes 49 are replaced with new ones or new components are replenished, hence allowing the component mounting apparatus to be operated without having a downtime.
However, in such a prior arrangement described above, the component feeder table 47 often exhausts all components before the other component feeder table 48 is made ready to replace the component feeder table 47, especially in a production of different models of circuit board 2 in small quantity, causing a downtime and declining the efficiency of production.
Similarly, when the circuit board 2 requires so many kinds of components that both tables 47 and 48 need to carry different types of components to be mounted, one table cannot be replenished while the other is in operation, causing reduction in productivity.
To solve these problems, the number of parts cassettes carried on the component feeder tables 47 and 48 may be increased. This, however, increases the total weight of the component feeder tables 47 and 48 and will prevent high-speed movements thereof. Also, it will take more time for filling the tables 47 and 48 with the parts cassettes 49 hence decreasing the efficiency of production.